I don't know about _all_ sporting events, but they were certainly included in the Atlanta Olympics:

http://en.wikipedia.org/wiki/Cuba_at_the_1996_Summer_Olympics

It seems from further reading that the US doesn't have sanctions against Cuban sport, but Cuba itself stops athletes from travelling to competitions in the USA. "The government of Cuba however, will not be sending competitors to the 'World Boxing Championships, based in the U.S. city of Chicago from October 21 to November 3; this to avoid the 'theft' of athletes.'" [source]

As far as know, there are no sanctions against Zim cricket. No one wants to play there because it's dangerous, not because Mugabe is a nutter.

Dubai and Abu Dhabi have to decide for themselves whether to allow Israeli sportsmen and women into the country. However, as I said up the page, it's going to do more damage to their reputation as hosts of major events than it will do to Israel's economy or culture.